In experiments bringing into play a particle beam and in particular a high energy particle beam, it is sometimes necessary to measure precisely the properties of the beam while minimising as much as possible the influence of the measurement. It is known for measuring these beams to resort to Schottky or PIN type detectors composed of a first layer of a p-doped semiconductor material, a second layer of an intrinsic semiconductor material and a third layer of an n-doped semiconductor material. This structure is going to give rise to an active zone mainly situated in the intrinsic layer in which are going to be created charges during the passage of the beam. In order to be able to measure these charges, it is known to connect an anode and a cathode on each side of the PIN structure. Generally, these detectors are produced in the thickness of a silicon wafer and may thus reach a thickness substantially equal to 300 μm. They thus absorb a non-negligible quantity of radiation. The first consequence of this absorption is to greatly perturb the beam during the measurement. Moreover, since radiation-matter interactions take place in an important volume of the material composing the detector, the degradation of the electrical and mechanical character of said detector may be very rapid. Finally, charges are created outside of the active zone and diffuse up to the electrodes adding noise to the measurement signal.
To resolve in part this problem of absorption, it is known to thin the part of the detector that the beam is made to traverse during the measurement. However, in order to collect the charges generated by the beam, it is indispensable to place electrodes in the path of the beam. The presence of these electrodes has two consequences. Firstly, the materials used for the manufacture of these electrodes absorb a non-negligible quantity of the beam. In addition, the structure of the detector has to be comprised entirely between the electrodes. Yet, as has already been specified, the active zone is mainly concentrated in the intrinsic zone of the semiconductor material. Put another way, a large part of the material traversed by the beam does not directly contribute to the detection.
There thus exists a need concerning a detector making it possible to measure a high energy particle beam while avoiding excessive absorption of said beam by the detector and while limiting the formation of undesired charges in the non-active zones.